Die bonding equipment

ABSTRACT

Die bonding equipment for fine pitch ball grid array package includes: a semiconductor chip pickup stage for inspecting a status of a loaded semiconductor chip and a corresponding position thereof; an alignment stage on which the semiconductor chip fixed on a mount head is aligned; a chip transfer unit for transferring the semiconductor chip from the semiconductor chip pickup stage to the alignment stage; a guide rail for guiding a mount tape frame; a status inspecting unit disposed at a selected position over the guide rail, for inspecting a status and a position of the land pattern on the mount tape frame; and a bonding unit for bonding the land pattern to the semiconductor chip which is mounted on the mount head. The equipment only bonds semiconductor chips (good or defective) to lands patterns having the same status (good or defective).

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to die bonding equipment andmethods for the fabrication of ball grid packages and more particularlyto a die bonding method capable of detecting a failure of a land patternon a mount tape before a chip transfer unit picks up a chip and capableof matching a good land pattern to a good semiconductor chip and afailed land pattern to a failed semiconductor chip.

[0003] 2. Description of the Related Art

[0004] Recently, technologies for packaging semiconductor chips haverapidly developed with the development of thin film formingtechnologies. Ball grid array packages, currently in use, are a resultof the application of such technologies. A ball grid array package usesa flexible tape in place of a lead frame. The flexible tape includes aconductive pattern formed thereon. One end of the conductive pattern issoldered to terminals of a printed circuit board by a solder ballinterposed therebetween, and the other end is bonded to bonding padsthat act as input and output terminals of a semiconductor chip.

[0005] In the fabrication of ball grid array packages, the process ofattaching solder balls is the last step, which provides variousadvantages in carriage and handling of elements for a die attachingprocess and in mass production. Ball grid array packages also makeunnecessary the trimming and forming processes that are indispensable infabrication of more conventional packages.

[0006] Recently developed chip scale packages have a fine pitch in whichthe pitch of solder balls ranges from a few tens of microns to a fewhundreds of microns and sizes of such packages approach about 120% ofthe chip sizes.

[0007] To form a fine pitch ball grid package, multiple land patternsare first formed on a rectangular, polyimide-based tape. Throughholesare formed at selected portions of the polyimide-based tape. The landpatterns include solder ball pads, which are on a first surface of thepolyimide-based tape such that each of the pads covers a correspondingthroughhole and has a circular plate shape. The land patterns alsoinclude conductive patterns that electrically connect to respectivesolder ball pads and extend to edges of the tape.

[0008] Beam leads, that is, the ends of the conductive patterns, aredie-bonded to respective bonding pads of semiconductor chip. For suchthe die bonding, rectangular openings or windows are formed at edges ofthe polyimide based tape. After the die bonding, an electrical testdetermines whether or not the land patterns have open or short failuresand from the electrical test, failed land patterns are marked. Anelastomer is attached to a second surface of the polyimide based tape.

[0009] Continuously, the polyimide based tape on which the elastomer isattached is rolled, and the rolled tape is cut to length, for example,to include a number of land patterns. Hereinafter, a rolled tape havingthe above mentioned unit length is referred to as one base mount tape. Abase mount tape's edge portions are attached to a square mount tapeframe using an adhesive tape.

[0010] Semiconductor chips separated by sawing a wafer are transferredto corresponding base mount tapes, and a press head die bonds bondingpads of each of the semiconductor chips with beam leads exposed throughopen windows of base mount tape.

[0011] Afterwards, base mount tapes having semiconductor chips attachedare subject to a solder ball attaching process. The solder ballattaching process attaches solder balls to solder ball pads through thethroughholes in the base mount tape. The above solder ball attachingprocess prepares multiple ball grid array packages having a fine pitch.The multiple ball grid array packages are separated into individual ballgrid array packages, and the individual ball grid array packages aretested. Thus, the above processes fabricate ball grid array packages.

[0012]FIG. 1 shows conventional die bonding equipment 100 forfabrication of ball grid array packages having a fine pitch. Referringto FIG. 1, die bonding equipment 100 generally includes a wafer mountframe stocker 5, a base mount stocker 10, a chip pickup table 15, and abonding unit 20 on a support plate 1. A chip transfer unit moves asemiconductor chip from the chip pickup table 15 to the bonding unit 20,and a guide rail unit 40 guides a base mount tape frame 35 from the basemount tape stocker 10 to the bonding unit 20. Multiple charge coupleddevice(CCD) cameras observe the operation of die bonding equipment 100.

[0013] In FIG. 1, the chip pickup table 15 faces an opening 50 of thewafer mount frame stocker 5 so that a wafer mount frame 45 carryingmultiple semiconductor chips can be loaded into or unloaded from thewafer mount frame stocker 5. A square chip tray 55 that is attached tothe chip pickup table 15 receives failed semiconductor chips. The chiptray 55 moves together with the chip pickup table 15 in an X-Y plane.

[0014] Meanwhile, an alignment table 65, which includes a mount head 60,is spaced apart from the chip pickup table 15. The mount head 60receives a semiconductor chip from the chip pickup table 15, moves thereceived semiconductor chip to the bonding unit 20, and aligns thesemiconductor chip for die bonding. To align the semiconductor chip, thealignment table 65 can freely move along X-Y coordinate axes as does thechip pickup table 15, and when the semiconductor chip is skewed from therequired orientation for bonding of the chip, the alignment table 65rotate the skewed semiconductor chip for the required alignment. Thealignment table 65 can also move along the Z coordinate axis direction.

[0015] Here, a chip transfer unit 25, which reciprocates between thechip pickup table 15 and the alignment table 65, transfers semiconductorchips from the wafer mount frame 45 of the chip pickup table 15. Thechip transfer unit 25 includes: a collet 70 (hereinafter referred to asthe first collet) for adsorbing and fixing good semiconductor chips witha vacuum; a collet 75 (hereinafter referred to as the second collet) foradsorbing and fixing failed semiconductor chips; and a moving block 80including a collet selection unit (not shown) that selects the first orsecond collet 70 or 75 for use. The chip transfer unit 25 also includesa straight line reciprocating unit (not shown) for transferring themoving block 80.

[0016] The described base mount tape stocker 10 is spaced away from thewafer mount frame stocker 5. The guide rail unit 40 extends from anopening 85 of the base mount tape stocker 10, and a base mount tapeframe received at the base mount tape stocker 10 is unloaded through theopening 85. The guide rail unit 40 includes a pair of guide rails 42 and44 that guide the base mount tape frame 35. Each of the guide rails hasa moving unit (not shown) for moving the base mount tape frame 35, whichis unloaded from the base mount tape stocker 10.

[0017] A bonding unit 20 is over the guide rails 42 and 44 and distantfrom the base mount tape stocker 10. The bonding unit 20 includes apress head 22, which moves up and down, and a bonding unit CCD camera24, which moves together with the press head 22. The press head 22 isover the base mount tape frame 35, and the mount head 60 is below thebase mount tape frame 35 so that the press head 22 faces the mount head60. The bonding unit CCD camera 24 checks the position of the base mounttape frame 35 as moved and simultaneously checks for a failed markformed during the production of the base mount tape.

[0018] In addition to the bonding unit CCD camera 24, the conventionaldie bonding equipment typically includes two other CCD cameras. A chippickup table CCD camera 17 is for determining a position of a failedsemiconductor chip or a good semiconductor chip among the chips sawedfrom a wafer, and an alignment table CCD camera 62 is for checking thealignment of a semiconductor chip on the mount head 60 of the alignmenttable 65.

[0019] Hereinafter, operation of conventional die bonding equipment isdescribed with reference to FIG. 1.

[0020] First, prior to starting the die bonding process, an operatordiscriminates failed semiconductor chips from a sawed wafer mounted onthe wafer mount frame 45 and manually loads the discriminated failedsemiconductor chips into the failed semiconductor chip tray 55. Thisavoids an increase in the loading time for loading of failedsemiconductor chips. Such increases in the loading time occur whenanother wafer is loaded to start a process after processing of a waferis completed, a corresponding land pattern to be bonded among base mounttapes is failed, and there are no failed semiconductor chips on thewafer mount frame 45.

[0021] The operator loads all failed semiconductor chips in the failedsemiconductor chip tray 55, and then an unloading unit unloads one sheetof wafer mount frame 45 from the wafer mount frame stocker 5 and fixesthe sheet to the chip pickup table 15.

[0022] The chip pickup table CCD camera 17 continuously imagessemiconductor chips on the chip pickup table 15 to discriminate betweengood semiconductor chips and defective semiconductor chips.

[0023] An X-Y table moves the chip pickup table 15 so that a goodsemiconductor chip is below the first collet 70 of the chip transferunit 25. To shorten the bonding time, the first collet 70 picks up andstands by with a good semiconductor chip.

[0024] Concurrently with the stand by of the first collet 70, the mounttape frame 35 is unloaded from the mount tape stocker 10 and moves tothe bonding unit 20 along the guide rail unit 40. At this time, thebonding unit CCD camera 24 of the press head 22 photographs a first landpattern that is being processed first, to thereby discriminate whetherthe first land pattern is good or defective.

[0025] Here, when the first land pattern is good, the good semiconductorchip adsorbed on the first collet 70 is moved onto the mount head 60 ofthe chip alignment table 65 and is then aligned. Thereafter, the alignedgood semiconductor chip is transferred onto a corresponding good landpattern of the base mount tape 30 by the movement of the mount head 60.After the transfer of the good chip, the press head 22 moves downwardand the mount head 60 moves upward, so that bonding pads of the goodsemiconductor chip are bonded to beam leads of the good land pattern.

[0026] Meanwhile, when the first land pattern as discriminated isdefective, the good semiconductor chip adsorbed and fixed on the firstcollet 70 returns to an original position. Then, the second collet 75instead of the first collet 70 picks up the defective semiconductor chipand moves the defective chip onto the mount head 60. Thereafter, thedefective chip is transferred to a corresponding defective land patternof the base mount tape 30 by the movement of the mount head 60 without aspecific alignment. After the transfer of the defective chip, the presshead 22 moves downward and the mount head 60 moves upward, so thatbonding pads of the defective semiconductor chip are bonded to beamleads of the defective land pattern.

[0027] The conventional die bonding equipment and method have thefollowing problems.

[0028] First, when a land pattern of the base mount tape to be diebonded is determined to be defective, the first collet 70 of the chiptransfer unit 25 holds good semiconductor chip. Therefore, the firstcollet 70 returns the good semiconductor chip to an original position.Instead of the first collet 70, the second collet 75 adsorbs and fixes adefective semiconductor chip on the mount head. Accordingly, a delayoccurs.

[0029] Second, the bonding unit CCD camera determines whether landpattern of the base mount tape is good or not the die bonding time.Accordingly, much time is spent in determining such the status of thesemiconductor chip.

[0030] Third, an operator must manually pick up a defectivesemiconductor chip from the wafer mount frame and then load thedefective semiconductor chip in tray 55. As a result, loading timeslengthen.

[0031] Fourth, when a use of a defective semiconductor chip that isreceived in the defective semiconductor tray is required, X-Y table hasto move the semiconductor chip tray below the second collet 75. As aresult, the time spent in picking up the received defectivesemiconductor chips increases.

SUMMARY OF THE INVENTION

[0032] It is therefore an object of the present invention to decreasethe die bonding time of a ball grid array package having a fine pitch bydetermining whether a corresponding land pattern of the base mount tapeon which a semiconductor chip is being die-bonded, is good or not beforea chip transfer unit picks up a semiconductor chip and thereby allowingthe chip transfer unit to pick up a semiconductor chip matching the landpattern.

[0033] It is another object of the present invention to shorten a timetaken in determining whether a land pattern of a base mount tape is goodby once performing such a determination during loading of the mounttape.

[0034] It is yet another object of the present invention to decrease atime taken in picking up defective semiconductor chips by establishingthe defective semiconductor chip tray at the lower face of the collet ofthe semiconductor chip transfer unit along trace of the collet andthereby allowing wafer extend table not to be moved in order to pick upa defective semiconductor chip.

[0035] It is yet another object of the present invention to shorten atime taken in loading defective semiconductor chips into defectivesemiconductor chip tray by allowing collet of semiconductor chiptransfer to perform a work for loading defective semiconductor chip intothe defective semiconductor chip tray.

[0036] Other objects and advantages of the present invention will bemore apparent in view of the description that follows.

[0037] One embodiment of the present invention is a die bonding methodfor a fine pitch ball grid array package. The die bonding methodincludes inspecting the status and position of a semiconductor chipwhich is on a mount frame and the status and position of a land patternof a mount tape, wherein the land pattern is on one surface of the mounttape and the other surface of the mount tape is attached to a surface ofthe mount frame. Thereafter, the status data and the position datacorresponding to the semiconductor chip and the land pattern inspectedare stored. After repeating the inspection of one or more semiconductorchip, a semiconductor chip is selected using the stored status data andthe position data of the semiconductor chip and the land pattern. Theselected semiconductor chip has a status matching to the status of theland pattern at a bonding region for the die bonding. The selected chipis transferred to an alignment region for an operation corresponding tothe status of the transferred chip.

[0038] Another embodiment of the invention is die bonding equipment forfine pitch ball grid array packages. The die bonding equipment includes:a semiconductor chip pickup stage for inspecting the status and positionof a loaded semiconductor chip, wherein a wafer mount frame is unloadedfrom a wafer mount frame stocker and the wafer mount frame is loaded onthe semiconductor chip pickup stage; an alignment stage spaced apartfrom the semiconductor chip pickup stage; a chip transfer unit fortransferring the semiconductor chip from the semiconductor chip pickupstage to the alignment stage; a guide rail for a mount tape frame havinga mount tape on which at least one land pattern is formed, the mounttape frame being transferred from a mount tape frame stocker in whichthe mount tape frame is received to a die bonding position adjacent tothe alignment stage; an inspection system disposed over the guide rail,for inspecting a status and a position of the land pattern on the mounttape frame; and a bonding unit for bonding the land pattern to thesemiconductor chip that is mounted on the mount head.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above objects and other advantages of the present inventionwill become more apparent by describing in detail a preferred embodimentthererof with reference to the attached drawings in which:

[0040]FIG. 1 is a perspective view of conventional die bondingequipment;

[0041]FIG. 2 is a perspective view of die bonding equipment according toan embodiment of the present invention;

[0042]FIG. 3 is a partial perspective view of portions of a transferunit and a chip pickup stage in the equipment of FIG. 2;

[0043] As FIG. 4 is a perspective view of a portion of the equipment ofFIG. 2 that removes the transfer unit body from the transfer unit;

[0044]FIG. 5 is a schematic diagram showing the positions of CCD camerasin the equipment of FIG. 2;

[0045]FIGS. 6A, 6B, and 6C together are a flow chart for a die bondingmethod for fine pitch ball grid array package;

[0046]FIG. 7 is a plan view of a wafer fixed on a wafer mount frame;

[0047]FIG. 8 is a plan view of a base mount tape fixed on a base mountframe; and

[0048]FIG. 9 is a schematic view of a memory table or data structurestoring status and position information for the land pattern of the basemount tape.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Die bonding equipment for ball grid array packages having finepitch according to the present invention is described more fullyhereinafter with reference to the accompanying drawings.

[0050]FIG. 2 is a perspective view of die bonding equipment 200 used forthe fabrication of ball grid array package having fine pitch accordingto one embodiment of the present invention. As major components, diebonding equipment 200 includes a support plate 201, a wafer mount framesupplying unit (stocker) 210, a chip pickup stage 220, a bonding unit260, a chip transfer unit 230, a chip alignment stage 240, a base mounttape supplying unit 250, a mount tape frame loader 290, a control module(not shown), and multiple charge coupled device (CCD) cameras.

[0051] Although not shown in the drawings, the control module includes acontrol unit such as a microprocessor and a memory unit for storingdata. Here, the memory unit permits data input and output and can be,for example, a harddisk driver (HDD) or a random access memory (RAM).The memory unit stores status information indicating whethersemiconductor chips are good or defective and position data for the goodor defective semiconductor chips. The memory unit also stores statusinformation indicating whether land patterns of a base mount tape 251are good or defective and position data for the land patterns.

[0052] The wafer mount supplying unit 210 is disposed on the supportplate 201 and includes a wafer mount frame stocker 214 and a mount framemoving unit 216. The wafer mount frame stocker 214, which typically hasa hexagonal shape, receives and stores a stack of wafer mount frames.The mount frame moving unit 216 loads or unloads a wafer mount frame 212from the wafer mount frame stocker 214. The mount frame moving unit 216includes a pneumatic cylinder and a gripper 216 a coupled to an end ofthe cylinder. The wafer mount supplying unit 210 has one open face 218such that movement of the mount frame moving unit 216 can load or unloadthe wafer mount frame 212 via the open face 218. The chip pickup stage220 is at a position corresponding to the open face 218 of the wafermount supplying unit 210.

[0053] The chip pickup stage 220 includes a ring shaped stage 222 and anX-Y table 224. The X-Y table freely moves the ring shaped stage 222 inan X-Y plane. A chip pickup stage CCD camera 226 is over the chip pickupstage 220 and allows an operator to acquire position data for good ordefective semiconductor chips among the semiconductor chips in pickupstage 220.

[0054] A guide rail 219 between the chip pickup stage 220 and the wafermount frame stocker 214 precisely guides the wafer mount frame 212 fromthe wafer mount frame stocker 214 to the chip pickup stage 220 andallows the wafer mount frame 212, which is being guided, to be alignedwith the ring shaped stage 222.

[0055] The chip alignment stage 240 is on the support plate 201 andspaced apart from the chip pickup stage 220. The chip alignment stage240 receives a semiconductor chip from the chip pickup stage 220 andmoves and/or rotates the semiconductor chip in the X-Y plane, to therebyalign the semiconductor chip for bonding. The chip alignment stage 240operates according to a control signal of the control module andincludes an X-Y table 246, a stage 248 on the upper surface of the X-Ytable 246, and a mount head 244. An alignment stage CCD camera 242 isover the chip alignment stage 240. The alignment stage CCD camera 242confirms the alignment status of the semiconductor chip that is adsorbedand fixed on the mount head 244.

[0056] The chip transfer unit 230 transfers semiconductor chips from thechip pickup stage 220 to the alignment stage 240. FIGS. 3 and 4illustrate features of an embodiment of the chip transfer unit 230,which is disposed between the chip pickup stage 220 and the chipalignment stage 240. As shown in FIG. 3, the chip transfer unit 230includes a transfer unit body 232, a collet unit 234, and a defectivesemiconductor chip tray 236. The transfer unit body 232 has a lengthgreater than the interval L between the central portion of the chippickup stage and the mount head 244 of the alignment stage 240.

[0057] As shown in FIG. 4, a pair of pulleys 237 a and 237 b are atopposite ends of the inner portion of the transfer unit body 232. Atension wire 238 is around pulleys 237 a and 237 b and moves whenpulleys 237 a and 237 b rotate. A servo motor 239 attached to arotational axis 239 a of pulley 237 a controls rotation of pulley 27 aand thereby controls the direction and distance that the tension wire238 moves.

[0058] The collet unit 234 includes a guide block 234 a coupled to thetension wire 238 and a guide bar, a collet support body 234 b coupled tothe guide block 234 a, a collet 234 c coupled to the collet support body234 b, and a collet displacement generating unit (not shown) for movingthe collet 234 c.

[0059] The defective semiconductor chip tray 236 is below the transferunit body 232. The defective semiconductor chip tray 236 is along thetransfer path of the collet unit 234, which allows the collet unit 234to load a defective semiconductor chip from the chip pickup stage 220and unload the defective semiconductor chip in a single row tosemiconductor chip tray 236.

[0060] Returning to FIG. 2, a long guide rail 253 for transferring thebase mount frame 251 is adjacent the chip alignment stage 240. The guiderail 253 has a guide groove (not shown) that couples to and guides thebase mount frame 251 during movement along the guide rail 253. At theguide groove, there are provided multiple driving rollers (not shown)for movement of the base mount frame 251 back and forth along the guiderail 253. A mount tape frame stocker 255, which holds a stack of thebase mount tape frames 251, is at one end of the guide rail 253, and themount tape frame loader 290, which holds a stack of base mount tapeframes 251 for which die bonding process is complete, is at the otherend of the guide rail 253.

[0061] The bonding unit 260, which performs the die bonding process, isat a central portion of the guide rail 253, and a CCD camera 257 forinspecting the land patterns is between the bonding unit 260 and themount tape frame stocker 255. The CCD camera 257 photographs the landpatterns of the base mount frame 251 for determination of statusinformation indicating whether the land patterns are good or defective.A conventional pattern recognition system (not shown) can determinewhether the land patterns are good or defective and store statusinformation to indicate the results. The collet 234 picks up a good ordefective semiconductor chip according to whether the status informationindicates a corresponding land pattern is good or defective.

[0062] The bonding unit 260 further includes: an X-Y table (not shown)which the control module operates; a movable press head 262 coupled tothe X-Y table; and a bonding unit CCD camera 264 fixed to the press head262. The bonding unit CCD camera 264 is for confirming alignment of theland pattern of the mount tape and the transferred semiconductor chipand correcting deviations from the required alignment.

[0063]FIG. 5 schematically shows a top view of the equipment 200 of FIG.2 and illustrates the positions of the CCD cameras 226, 257, 242, and264 in a camera frame 270. In FIG. 5, symbol C1 represents the chippickup stage CCD camera 226 which is over the chip pickup stage 220, C2represents the CCD camera 257 for determining whether the land patternsare good or defective, C3 represents the alignment stage CCD camera 242,and C4 represents the bonding unit CCD camera 264.

[0064] The die bonding equipment 200 of FIG. 2 can perform a die bondingprocess illustrated in FIGS. 6A, 6B, and 6C. Prior to the die bonding, awafer on which processes for the fabrication of a plurality ofsemiconductor chips have been completed, is prepared and is mounted onone of the wafer mount frames 212. The wafer mount frame 212 has adiameter greater than that of the wafer. At this time, the backside ofthe wafer is attached to the wafer mount frame 212. The wafer is thensawed along the scribe lines to separated individual chips. The wafermount frames 212, each having multiple separated semiconductor chips,are loaded into the mount frame stocker 214.

[0065] In an initial step ST10 of the die bonding process, the mountframe moving unit 216 unloads one of the wafer mount frames 212 thatcontains separated semiconductor chips, from the mount frame stocker 214and then loads the mount frame 212 onto the ring shaped stage 222 of thechip pickup stage 220.

[0066] Thereafter, an inspection step ST20 using the chip pickup stageCCD camera 226 visually inspects any one of the separated semiconductorchips on the wafer mount frame 212 and classifies the inspectedsemiconductor chip as good or defective.

[0067] Meanwhile, a step ST30 unloads from the mount tape frame stocker255 a base mount tape frame 251 having a base mount tape to which asemiconductor chip will be die-bonded. A step ST40, which is duringunloading of the base mount tape frame 251 from the mount tape framestocker 255 and transfer to the bonding unit 260, includes a visualinspection of the base mount tape using CCD camera 257 to determinewhether land patterns on the base mount tape 251 are good or defective.The status information indicating the results of the determination arethen stored in the memory device.

[0068]FIG. 8 shows a base mount tape 251, and FIG. 9 shows a datastructure 500 that includes status data corresponding to the base mounttape 251. For step ST40, the CCD camera 257 photographs land patternsC11, C12, and C13 first and determines whether the photographed landpatterns are good or defective. The determined status information forthe land patterns C11, C12, and C13 are stored at addressescorresponding to entries T11, T12, and T13 in data structure 500 of FIG.9.

[0069] In the example of FIGS. 8 and 9, the land patterns C11 and C13did not fail the inspection and are determined to be good land patterns.Accordingly, corresponding entries T11 and T13 of the data structure 500store a value G. In this example, the land pattern C12 failed the visualinspection and is determined to be defective. Accordingly, thecorresponding entry T12 stores a symbol F. Visual inspection similarlydetermines the status information for all land patterns, for example, 30land patterns of the base mount tape attached on the base mount tapeframe 251 of FIG. 8, and the determined status data are stored incorresponding addresses of the data structure 500.

[0070] A step ST50 transfers the base mount tape frame 251 to thebonding unit 260 while visual inspection continues. After the visualinspection is completed and inspection data of land patterns are stored,a step ST60 determines from the status information in the data structure500 whether a first land pattern for a die bonding process is good ordefective.

[0071] When the first land pattern is good, the process transfers fromstep ST60 to a step ST70. Step ST70 uses the status information storedin the memory device for the semiconductor chips and determines whethera semiconductor chip currently positioned for transfer for the diebonding process is good or not.

[0072] From step ST70, when the inspected semiconductor chip proves tobe defective, step ST75 stores the defective semiconductor chip in thedefective semiconductor chip tray 236. Thereafter, step ST77 visuallyinspects another semiconductor chip on the chip pickup stage 220 beforethe process returns to step ST70. A matrix such as illustrated in FIG. 7can store the status information for the semiconductor chips from thechip pickup stage 220. Each semiconductor chip from the chip pickupstage 220 has a corresponding matrix element, and the value of thecorresponding matrix element indicates whether the chip is good ordefective. In the example of FIG. 7, dots mark the defective chips. Forexample, a matrix element [23] corresponding to a semiconductor chip inrow 2 and column 3 and matrix element [24] corresponding to asemiconductor chip in row 2 and column 4 indicate that the correspondingchips are defective.

[0073] When step ST70 determines the semiconductor chip is good, thechip transfer unit 230 adsorbs and picks up the good semiconductor chipin a step ST80.

[0074] In a step ST90 (FIG. 6B), the chip transfer unit 230 transfersthe good semiconductor chip to the mount head 244 of the chip alignmentstage 240. The chip alignment stage 240 precisely aligns the chip in thedie bonding position in a step ST100, subsequent to transferring of thesemiconductor chip to the bonding unit 260 in a step ST110. Morespecifically, in step ST100, the alignent stage CCD camera 242photographs the good semiconductor chip when transferred onto the chipalignment stage 240. When photographing indicates an alignment failure,the mount head 244 having the good semiconductor chip thereon rotates ormoves up or down to align the good semiconductor chip. After thealignment is complete, the mount head 244 loads the good semiconductorchip onto the bonding unit 260 in step ST110.

[0075] At this time, the base mount tape frame 251 has been loaded onthe bonding unit 260 and awaits the bonging process. When both of a goodsemiconductor chip and a base mount tape frame 251 are loaded onto thebonding unit 260, the bonding unit CCD camera 264 inspects whether beamleads of the land patterns formed on the base mount tape of the basemount tape frame 251 are precisely aligned with bonding pads of the goodsemiconductor chip. A step ST120 aligns the base mount tape and the goodsemiconductor chip for beam lead bonding. After the step ST120, a stepST130 is the beam lead bonding that the bonding unit 260 performs.

[0076] After a certain time elapses, step 140 determines whether or notanother land pattern for die bonding still remains. If a land patternfor die bonding does not remain, die bonding process is complete. If aland pattern for die bonding still remains, the process returns to stepST20, which determines whether the semiconductor chip that is being diebonded to the land pattern is good or bad. The visual inspectionclassifies the semiconductor chip as good or defective, and theclassification result is stored. In addition, inspection step ST60 againdetermines from the stored status data whether a land pattern that isbeing die-bonded is good or defective. If in step ST60 the land patternproves not to be good, the process proceeds to a step ST150, whichdetermines whether or not there is a defective semiconductor chip in thefail semiconductor chip tray 236. When no defective semiconductor chipsremain in the semiconductor chip tray 236, the collet 234 picks up adefective semiconductor chip that is identified from the position datathat was stored in step ST75. Otherwise, when the semiconductor chiptray 236 contains a defective semiconductor chip, the collet 234 picksup a defective semiconductor chip from the semiconductor chip tray 236.In a step ST170, the chip transfer unit 230 transfers the defectivesemiconductor chip as picked up to the mount head 244 of the chipalignment stage 240.

[0077] For a defective semiconductor chip transferred to the chipalignment stage 240 through such the steps ST140 to ST170, a step ST180transfers the defective semiconductor chip directly to the bonding unit260 without an alignment process. The bonding unit 260, in a step ST190,performs die bonding for such defective semiconductor chips anddefective land patterns.

[0078] After step ST190, a step ST200 determines whether or not a landpattern remains for die bonding and another die bonding is needed. If aland pattern for die bonding remains, the process returns to the stepST20 and repeatedly performs the steps from ST20 to ST200. When no landpattern remains for further die bonding, a step ST210 determines whetherthe semiconductor chip tray 236 has room for another defectivesemiconductor chip. When there is a vacant site in the semiconductorchip tray 236, the chip transfer unit 230, in a step ST220, loads adefective semiconductor chip from the wafer mount frame 212 onto thesemiconductor chip tray 236.

[0079] As described previously, the present invention prevents amismatched bonding such as die bonding a good semiconductor chip to adefective land pattern or die bonding a defective semiconductor chip toa good land pattern. In particular, visual inspection determines whethera land pattern that is being die-bonded to a selected semiconductor chipis good or defective prior to the picking up of the semiconductor chip.Moverover, the invention enhances a productivity during the die bondingprocess by automatically transferring the defective semiconductor chipsinto the semiconductor chip tray using the bonding unit.

[0080] The present invention is not limited to the above-describedembodiments. Various changes and modifications may be effected andremain within the scope of the invention, as defined by the appendedclaims.

What is claimed is:
 1. A die bonding method for fine pitch ball gridarray package comprising: inspecting a status of a semiconductor chip,which is on a first mount frame containing a plurality of semiconductorchips, and a status of a land pattern of a mount tape, wherein the landpattern is formed on one surface of the mount tape and the other surfaceof the mount tape is attached to a second mount frame; transferring themount tape to a bonding unit after the inspecting of the land pattern;selecting one of the semiconductor chips that has a status correspondingto the status of the land pattern; and transferring the selected chipfor bonding to the land pattern.
 2. The die bonding method of claim 1 ,further comprising storing status data resulting from the inspecting,wherein the status data represents whether each land pattern of themount tape is good or defective.
 3. The die bonding method of claim 1 ,wherein transferring the selected chip comprises: moving the selectedchip to the land pattern after performing an alignment if the selectedchip is good; and moving the selected chip to the land pattern withoutperforming an alignment if the selected chip is defective.
 4. The diebonding method of claim 3 , wherein if the selected chip is good, thetransferring further comprises further aligning the good semiconductorchip with the land pattern, after transferring the selected chip to theland pattern which is placed at the die bonding region.
 5. The diebonding method of claim 1 , wherein inspecting the semiconductor chipscomprises: inspecting the status of the semiconductor chip using a firstCCD camera for a chip inspection; and inspecting the status of the landpattern using a second CCD camera between a mount tape stocker and a diebonding unit.
 6. The die bonding method of claim 5 , wherein theinspecting of the land pattern is performed before the selected chiparrives at the die bonding unit.
 7. The die bonding method of claim 6 ,wherein the second CCD camera inspects the land pattern when the landpattern is temporarily stopped.
 8. The die bonding method of claim 6 ,wherein the second CCD camera inspects the land pattern when the landpattern is moving.
 9. The die bonding method of claim 1 , wherein theselecting determines whether the land pattern that is at the die bondingregion is good or defective, if the land pattern is good, the selectingselects a good semiconductor chip; and if the land pattern is defective,the selecting selects a defective semiconductor chip.
 10. The diebonding method of claim 9 , wherein when the land pattern is good and aninspected semiconductor chip on the mount frame is defective, theselecting comprises: storing a position of the defective semiconductorchip in a memory; inspecting another of the semiconductor chips; andselecting a semiconductor chip that is good from among the semiconductorchips.
 11. The die bonding method of claim 10 , wherein when the landpattern is defective, the selecting comprises: determining whether asemiconductor chip tray disposed on a transfer path of a chip adsorptionmember contains a defective semiconductor chip, the chip adsorptionmember being disposed in a chip transfer unit that connects a chippickup region and an alignment region; and when no defectivesemiconductor chip is in the semiconductor chip tray, using the chipadsorption member to adsorb a defective semiconductor chip from thefirst mount frame, the defective semiconductor chip being identifiedfrom the position which is stored in the memory, and then transferringthe adsorbed defective semiconductor chip to the alignment region. 12.Die bonding equipment comprising: a semiconductor chip pickup stage ontowhich a wafer mount frame is loaded; an alignment stage spaced apartfrom the semiconductor chip pickup stage; a chip transfer unit capableof selecting a semiconductor chip from a wafer mount frame loaded on thesemiconductor pickup stage and transferring the semiconductor chip fromthe semiconductor chip pickup stage to the alignment stage; aninspection unit for inspecting a status and a position of land patternson a mount tape frame during movement of the mount tape for bonding; anda bonding unit for bonding a land pattern from the inspection unit tothe semiconductor chip from the alignment stage.
 13. The die bondingequipment of claim 12 , wherein the inspection unit comprises a chargecoupled device (CCD) camera.
 14. The die bonding equipment of claim 12 ,wherein the chip transfer unit comprises: a linear reciprocating unit; asemiconductor chip adsorption unit coupled with the linear reciprocatingunit and reciprocating along a path between the semiconductor chippickup stage and an alignment stage; and a semiconductor chip traydisposed along the path of the semiconductor chip adsorption unit, thesemiconductor chip tray have capacity to receive at least one defectivesemiconductor chip.
 15. The die bonding equipment of claim 14 , whereinthe semiconductor chip tray comprises a receiving part on which at leastone semiconductor chip is received, the receiving part being formed inone row.
 16. The die bonding equipment of claim 14 , wherein thesemiconductor chip adsorption unit comprises: a pair of pulleys spacedapart from each other; a tension wire rolled on the pair of pulleys; achip adsorbing module coupled with the tension wire, for adsorbing andfixing a semiconductor chip with a vacuum pressure; and a driving motorcoupled to one of the pair of pulleys, for reciprocating the tensionwire and thereby transferring the chip adsorbing module by a selecteddistance.
 17. A die bonding method comprising: (a) inspecting a landpattern; (b) in response to the inspecting indicating that the landpattern is good, performing a first selection process that comprises:(b1) inspecting a chip that is on a wafer mount frame; (b2) if theinspecting of the chip indicates the chip is good, selecting the chipfor bonding to the land pattern and ending the first selection process;and (b3) if the inspecting of the chip indicates the chip is defective,inspecting another chip if any remains in the wafer mount frame thatprevious inspecting has not indicated as defective and returning to step(b2); and (c) in response to the inspecting indicating that the landpattern is defective, performing a second selection process that selectsa defective chip for bonding to the land pattern.
 18. The die bondingmethod of claim 17 , wherein the first selection process furthercomprises storing status data indicating a chip is defective if theinspecting indicates that the chip is defective.
 19. The method of claim18 , further comprising moving a chip that inspecting indicated wasdefective, to a tray.
 20. The die bonding method of claim 19 , whereinthe second selection process comprises: selecting a defective chip fromthe tray for bonding to the land pattern if the tray is not empty; andselecting a defective chip from the wafer mount frame for bonding to theland pattern if the tray is empty.